Priming mixture



Patented Nov. 15, 1938 a STA 2,136,801 PRIMING MIXTURE Joseph D. McNutt, New Haven, Conn., assignor to Winchester Repeating Arms Company, New Haven, Conn., a corporation of Maryland No Drawing.

Application December 7, 1936,

Serial No. 114,641

11 Claims.

This invention relates to priming mixtures for small arms ammunition and more particularly to a non-corrosive priming mixture. In recent years priming mixtures for small arms ammunitionhave been of the non-corrosive type, that is, the potassiumchlorate formerly used as the oxidizing agent has been-eliminated from such mixtures and other salts used in its place. The oxidizers most generally used and the trate, lead nitrate and the double salt of barium and potassium nitrate. While the use of these salts has been an advance in the art in that the corrosive effects of the use of potassium chlorate have been eliminated, the non-corrosive priming mixtures so produced are sluggish on ignition and poor ignition of the propellent powder therefore results. This is due to the high temperatures of decomposition of the salts mentioned. All of them decompose at temperatures far above those desired so that the oxygen is not available at the most important time during combustion of the priming mixture. This lack of oxygen results in poor sensitivity of the mixtures at the most critical period of decomposition.

To overcome this defect in the non-corrosive priming mixtures, I propose the use of a small amount of a hypophosphite. I have found that the presence of a small percentage of hypophosphites lowers the decomposition point of priming mixtures containing barium nitrate, lead nitrate or the double salt of barium and potassium nitrate. This produces better combustion of the priming mixture and therefore results in better c ignition of the propellent powder. While a number of the hypophosphites will give the desired result, I have found that the use of lead hypophosphite is particularly advantageous in conjunction with oxidizers whose decomposition temperature is above 200 C. I therefore propose to add a small percentage of lead hypophosphite to various noncorrosive priming mixtures in which barium nitrate, lead nitrate or the double salt of barium and potassium nitrate is employed as an oxidizer.

The following are typical examples of priming mixtures in which lead hypophosphite is added to the mixture for the purpose of lowering the decomposition temperature of the mixture:

From 27-33 %preferably 30 From 4- 7 %preferably 5 From 3238%preferably 35 From 2228%-preferably 25% From 4- 7 %preferably 5% From 3238%-preferably 35% Basic lead styphnate From 5 9%-preferably 7% Barium nitrate From 2832%-preferably 30% Calcium silicide From 4 8%-preferably 6% Antimony sulphide From 15-20 %preferably 17% Lead hypophosphite From 4- 7 %preferably 5% Fulminate of mercury Potassium dinitrophenylazide Double salt of barium and, potassium nitrate Antimony sulphide Lead hypophosphite Fulminate of mercury Lead hypophosphite--- From 5- 9%-preferably 7% The first two mixtures given above containin mercury fulminate as an initiator and potassium dinitrophenylazide or basic lead styphnate 'as sensitizer are suitable for use in the preparation of primers for shot shell cartridges or for metallic 5 cartridges of the center fire type. The third formula employing lead styphnate (the normal lead salt of trinitro-resorcine) as an initiator and a a fuel is suitable for use in the preparation of rim ones found most useful have been barium ni-.-

provided with perforations to mold pellets of the proper ,size and weight. These pellets are then transferred either into priming cups for shot shell cartridges or for center fire ammunition or into empty rim fire cartridgeshells' in the usual way. h

-In connection with rim fire ammunition the charge is forced to distribute itself in the hollow rim by spinning each shell in the customary rim fire loading machines. After the shells have been properly primed, they are loadedwith powder and shot or bullets in the customary way.

The formulae given above illustrate the use of lead hypophosphite with various initiators, sensitizers and fuels in combination with difflcultly deco posable oxidizers, such as barium nitrate, lead itrate and the double salt of barium and potassium nitrate. The invention is not limited to the particular well known priming ingredients disclosed but is capable of use in connection with other initiators, sensitizers, fuels and difflcultl decomposable oxidizers.

I claim:

1. A priming mixture adapted to ignite a propellent charge comprising an initiator, a fuel, an oxidizing agent and lead hypophosphite.

2. A priming mixture adapted to ignite a propellent charge comprising an initiator, a fuel, an oxidizer from the group consisting of barium nitrate, lead nitrate and the double salt of barium and potassium nitrate and lead hypophosphite.

3. A priming mixture adapted to ignite a propellent charge comprising mercury fulminate, potassium dinitrophenylazide, the double salt of barium 'and potassium nitrate, antimony sulphide and lead hypophosphite.

4. A priming mixture adapted to ignite a propellent charge comprising from 27 to 33 percent mercury fulminate, from 4 to 7 percent potassium dinitrophenylazide, from 32 to 38 percent of the I double salt of barium and potassium nitrate, from 22 to 28 percent antimony sulphide, and

from 4 to 7 percent lead hypophosphite.

5. A priming m xture adapted to ignite a propellent charge comprising substantially 30 percent mercury fulminate, substantially 5 percent potassium dinitrophenylazide, substantially 35 percent of the double salt of barium and potassium nitrate, substantially 25 percent antimony sulphide and substantially 5 percent lead hypophosphite.

6. A priming mixture adapted to ignite a propellent charge comprising mercury fulminate, basic lead styphnate, barium nitrate, calcium silicide, antimony sulphide and lead hypophosphite.

7. A priming mixture adapted to ignite a propellent charge comprising from 32 to 38 percent mercury fulminate, from 5 to 9 percent basic lead 1 styphnate, from 28 to 32 percent barium nitrate,

from 4 to 8 percent calcium silicide, from to percent antimony sulphide and from 4 to 7 percent lead hypophosphite.

8. A priming mixture adapted to ignite a propcllent charge comprising substantially 35 percent mercury fulminate, substantially '7 percent basic lead styphnate, substantially 30 percent barium nitrate, substantially 6 percent calcium silicide, substantially 17 percent antimony sulphide and substantially 5 percent lead hypophosphite.

9. A priming mixture adapted to ignite a propellent charge comprising lead styphnate, lead nitrate, ground glass and lead hypophosphite.

10. A priming mixture adapted to ignite a propellent charge comprising from 37 to 43 percent lead styphnate, from 28 to 32 percent lead nitrate, from 20 to percent ground glass and from 5 to 9 percent lead hypophosphite.

11. A priming mixture adapted to ignite a propellent charge comprising substantially 40 percent lead styphnate, substantially percent lead nitrate, substantially 23 percent ground glass and substantially 7 percent lead hypophosphite.

JOSEPH D. Mo. 

